# Rainbow4

Canonical URL: https://colorcurio.us/colormaps/colorcet.rainbow4
Source type: Colormap
Type: sequential
Collection: colorcet
Attribution: Kovesi 2015 — "Good Colour Maps: How to Design Them" (arXiv:1509.03700)
License: CC-BY-4.0
Source: https://raw.githubusercontent.com/holoviz/colorcet/main/assets/CET/rainbow_bgyr_10-90_c83_n256.csv
Tags: perceptually-uniform, rainbow
Stops: 256

## Summary

Rainbow4 is a sequential colormap from the colorcet collection. Inspect its perceptual lightness, chroma, and hue profile on colorcurio.us.

## Perceptual profile (OKLCh)

- Lightness: 0.243 → 0.553 (range 0.645, min 0.243, max 0.889); non-monotonic; midpoint 0.742
- Chroma: min 0.092, max 0.262, mean 0.197
- Hue: 265.7° → 28.4° (span 237.3°), path monotonic-ccw; quadrants: blue, azure, cyan, mint, green, chartreuse, yellow, orange, red
- Endpoint temperature: cool → warm
- Perceptual ΔE: total 196.0, mean/step 0.769, max step 3.108, smoothness 0.291, speed 0.769

## Colorblind safety (ΔE under simulated CVD)

- Protanopia: ΔE total 157.6; preserves order: no
- Deuteranopia: ΔE total 144.4; preserves order: no
- Tritanopia: ΔE total 151.1; preserves order: yes

## Related

- Family: https://colorcurio.us/colormaps/families/colorcet
- All colormaps: https://colorcurio.us/colormaps